On a thin rubber mattress in a Kenyan village, the Robertson twins from Hamilton slept top and tail for six months. By choice. They labelled their room "the concrete cell".

Seven years on, and the 24-year-olds named Zane and Jake will join compatriot Nick Willis in the Commonwealth Games 5000m early tomorrow, starting to see the fruits of their hard toil and high kilometres.

The pair are the mystery men of New Zealand athletics and weren't sighted at last week's pre-Games team camp in Cardiff. Requests for telephone interviews were politely declined by their handlers.

Devotees to altitude training, they finalised their preparations in Kenya (Jake) and St Moritz (Zane). Both delayed their arrivals to within 48 hours of their opening race, and will back up in the 10,000m (Jake) and 1500m (Zane).

Jake Robertson sowed the seed, after rooming with Kenyans at a world cross-country championships as a teenager. The ultimate distance running finishing school beckoned, the town of Iten at 2400m above sea level, which churned out top Kenyan runners.

The duo's times did the talking and they sit inside the top five in New Zealand's proud middle distance history; Jake fourth-fastest in the 5000m and third in the 10,000m, Zane third in the 5000m and fifth in the 1500m.

"They're unique personalities, and their stories are quite amazing," said Scott Goodman, high performance director for Athletics New Zealand.

"They can do something special, which they might at this competition, and which I think they will over the next 4-5 years."

One slight concern for Jake was getting to Glasgow, given the monumental journey out of Africa which had already been delayed a day due to flight cancellations. He seemingly used up his bad luck on the eve of big events, when he slipped in the bath and ruined his chances on the eve of last year's Moscow world championships.

Zane, meanwhile, is in form. He finished 13th in the 5000m in Moscow after his brother's misfortune then, in Ireland this month, climbed to fourth on the all-time New Zealand lists in both the mile (3min 53.72sec) and 3000m (7min 41.37sec) with two quality performances.

Jake is harder to get a line on, having remained in Kenya, but Goodman said the grapevine was strong. "He has a training partner there called Chegs, who assures us that Jake's in the best shape he's been for about 18 months."

Zane Robertson said in 2012: "I'm so thankful we went through those hardships, because going through them, the way Kenyans do, if you survive you can go through anything."

Willis, whose brother Steve coaches the pair, continues to marvel at the twins.

"There aren't many people in New Zealand who are more dedicated to one particular goal. They're putting all their eggs in one basket," Willis said.

"Normally in the western world you say ‘get an education and have a nice cushy mattress to fall onto'. But they've thrown caution to the wind and there's nothing to fall back on if running doesn't work out. That's why they've been able to make those jumps."

Zane Robertson's 5000m PB of 13min 13.83sec is nearly 2sec quicker than his brother and 7sec faster than Willis, a relative novice in the longer event. In tomorrow's 5000m the trio will avoid Olympic champion Mo Farah, a late withdrawal, but face Kenya's world indoor 3000m champion Caleb Ndiku, who the Robertsons know.

"The amazing thing too is their attitude to racing the Kenyans. They're not put off by them, they train with them on a daily basis," Goodman said.

Willis is a huge chance in the 1500m with Kenyan flyers Absel Kiprop and Silas Kiplagat absent. Zane Robertson and Julian Matthews provide the backup cast to Willis, by which time the twins may well have announced themselves to a wider audience.